Graff Diamonds has sold a diamond ring for €7 million ($11 million) at the Tefaf art and antiques fair in the Dutch city of Maastricht. The jewellery piece contains a 70.12 carat yellow diamond set in a platinum ring, bought by an undisclosed European client. With the backdrop of the US economic slump, fewer American buyers attended the fair, while the European demand continued to be robust. The demand for diamonds is surpassing its supply, as is evident by the fact that the prices of diamonds are increasing.